In fact, it is easier to replicate this problem... For example, if you have Samba4 working okay in an IPv4-Only environment and then, you just enable IPv6 (and reboot), Samba4 will not start anymore...
Also, I tried to run "samba_dnsupdate --verbose" after enabling IPv6 at etc/network/interfaces (ifdown eth0 ; ifup eth0) and, before a reboot (while Samba4 is still running), without success...
I did more tests this weekend on this...
In fact, it is easier to replicate this problem... For example, if you have Samba4 working okay in an IPv4-Only environment and then, you just enable IPv6 (and reboot), Samba4 will not start anymore...
Also, I tried to run "samba_dnsupdate --verbose" after enabling IPv6 at etc/network/ interfaces (ifdown eth0 ; ifup eth0) and, before a reboot (while Samba4 is still running), without success...